A WOMAN whose husband was killed in an Islamic State attack last year is suing Twitter over his murder.

A lawsuit filed by Tamara Fields of Florida alleges the San Francisco-based microblogging giant breached the US Anti-Terrorism Act by “spreading extremist propaganda” that directly led to the death of private contractor Lloyd “Carl” Fields Jr at a training centre in Jordan.

Fields was one of five people killed after a Jordanian former police captain went on a shooting rampage at the Amman compound on November 9. IS took responsibility for the attack and promoted it on social media.

The federal suit, believed to be the first attempt to hold Twitter civilly responsible under the Act, also alleges Twitter is instrumental to IS’s fundraising and recruitment efforts.

It claims Twitter “purposefully, knowingly or with wilful blindness” provided “material support to the preparation and carrying out of acts of international terrorism, including the attack in which Lloyd Fields Jr. was killed”.

“Twitter has knowingly permitted the terrorist group ISIS to use its social network as a tool for spreading extremist propaganda, raising funds, and attracting new recruits,” the complaint said.

“This material support has been instrumental to the rise of ISIS (whose members) members use Twitter to post instructional guidelines and promotional videos, referred to as ‘mujatweets’.”

Lloyd ‘Carl’ Fields Jnr, 46, was one of five people gunned down in an attack on a police training centre in Jordan last November

Twitter responded by expressing sympathy for Ms Fields’ loss but said it did not believe she had grounds to sue and appeared to uphold its users right to free speech. It said its own employees had been subject to death threats relating to the suspension of accounts supporting IS.

“While we believe the lawsuit is without merit, we are deeply saddened to hear of this family’s terrible loss. Like people around the world, we are horrified by the atrocities perpetrated by extremist groups and their ripple effects on the internet,” the company said in a statement.

“Violent threats and the promotion of terrorism deserve no place on Twitter and, like other social networks, our rules make that clear. We have teams around the world actively investigating reports of rule violations, identifying violating conduct, partnering with organisations countering extremist content online, and working with law enforcement entities when appropriate.”

Twitter says it is perpetually suspending accounts with links to terrorist groups, acting when it becomes aware of them. But hacktivists such as Anonymous and affiliates CtrlSec,GhostSec,WauchulaGhost and others say Twitter has been utterly negligent in its handling of IS and its supporters, compelling them to identify and sometimes take down such accounts themselves.

“Twitter needs to step up the pace if they want to do their part in removing Islamic State propaganda,” WauchulaGhost told news.com.au today.

“They can start by using software that has already been developed to search and remove the graphic content. We (Anonymous affiliated groups) are reporting thousands of accounts, images and videos. But we don’t see them going away fast enough. Anonymous and the Citizens of the World have basically been doing Twitter’s job.

“There are thousands of Anons and normal people that are searching and reporting this content. These people to not get paid nor want to be. We just want one thing and that’s to remove ISIS from social media. No one in social media or government is thinking about our future generation, our children. Kids see this content daily. It has to stop. Twitter, Cloudflare, Facebook, Instagram, Telegram etc, all social media outlets need to step up.”

The lawsuit cites a 2015 study by Washington-based think tank The Brookings Institution which found there were up to 70,000 pro-IS accounts on Twitter. The report came after the FBI issued a warning about American teens being susceptible to IS recruitment tactics.

This logo combining Twitter with the Islamic State flag has been tendered as part of Ms Fields’ complaint

A screenshot of one of the tweets tendered to federal court with Ms Fields’ complaint

The suit, which included screenshots of several IS propaganda images posted on Twitter, and describes how IS accounts with thousands of followers have rapidly reappeared following the company’s efforts to delete them.

“Even when Twitter shuts down an ISIS-linked account, it does nothing to stop it from springing right back up,” citing the example of an account called “@TurMedia333” that remerged as “@TurMedia334” and “@TurMedia335″ after the company shut it down.

Ms Fields’ case is compelling but faces a serious obstacle in the form of a law called the Communications Decency Act (CDA).

However, Ms Fields’ lawyer Joshua Arisohn did not believe the law would be much use to Twitter in the context of his client’s suit.

“The CDA is meant to give social media companies cover when their users commit libel,” he told Fortune.

“But Congress did not intend to give companies like Twitter a get out of jail free card when they knowingly hand over powerful communications tools to designated terrorist organisations so that they can recruit, fundraise and spread propaganda.”